An e-mail message that is over the attachment size limit is moved to the "Drafts" folder. And the Entourage/Outlook 2011 client generates one of the below
To resolve this issue, we need to follow below steps on the Exchange Client Access Servers in order to allow large attachments for EWS clients such as Entourage and Mac Outlook
Open "IIS Manager" > select "Default Web Site" > Click "Advanced Settings" > select "Connection Timeout"
and change the value in
Seconds (make sure the value is greater than the time it take to upload the file)
For this reason
set the above limits (step 1 to 5) to about double the original attachments' file size.
Increasing the allowed attachment size may cause performance issues in the Exchange environment. You have to consider the increase load a large attachment puts on the server infrastructure. You may experience one or more of the following symptoms if the attachment
size is increased: